The present invention relates to improved skin moisturizing and lubricating compositions which are additionally adapted for serving as carriers for pharmaceutically active agents in which form they are useful in the treatment of skin irritations, burns or infections. More particularly, this invention relates to optically clear, transparent, highly stable moisturizing and lubricating compositions having the additional utility aforenoted.
Oil free, non-greasy skin treatment compositions for counteracting moisture loss and promoting healing of the skin, as for example, burned or sun-burned skin are known.
In U.S. Pat. No. 4,837,019, compositions for counteracting moisture loss and promoting the healing of burned skin are described which include as the moisturizing and/or healing agent a component formed of polyglyceryl methacrylate, glycerine, allantoin, panthenol, amino acid complex, and fibronectin. The component aforedescribed is present in an amount of a 2-30% of the total composition, the make up of the remainder of the composition being dependent on whether the composition is in the form of an emulsion, cream, gel, aqueous/alcoholic or glycol solution or microemulsion.
The compositions of U.S. Pat. No. 4,837,019 have been found not to be stable undergoing phase separation on storage. In accordance with U.S. Pat. No. 4,863,725, moisturizing compositions are provided which are clear, oil-free and therefore non-greasy to the skin and touch which include as the major moisturizing component a composition derived from glycerol and acrylic or methacrylic polymers (polyglyceryl methacrylate), one or more skin feel enhancers which is preferably a polyol, one or more preservatives, and water as a carrier. The moisturizer composition also preferably includes one or more thickeners, one or more skin conditioning agents, one or more astringents and/or colorants and/or fragrances. The aforesaid moisturizing compositions may be in the form of clear lotions or gels.
In accordance with the present invention, an improved skin moisturizing and lubricating composition is provided which is a clear transparent, highly stable composition in gel form which comprises the product obtained by combining polyglyceryl methacrylate with a pharmaceutically acceptable silicone under condition of elevated pressure falling within the range of about 13,000 to 50,000 psi in the presence of a suitable emulsifier.
The polyglyceryl methacrylate employed contains approximately 50% water, is in the form of a white transparent gel and may or may not contain incidental ingredients, such as propylene glycol which may be present in an amount of 2% or less. A preferred polyglyceryl methacrylate is Lubrajel CG, a registered trademark of United Guardian Inc., which is distributed by Meadow Technical Corp., Livingston, N.J. The preferred form of Lubrajel has a viscosity at 20xc2x0 C. (Brookfield RTV) ranging from about 400,000 to about 5,000,000, a specific gravity of 1.2 mg/ml, is completely soluble in water and is substantially stable at 250xc2x0 F., even after sealed storage for 3 years at 20xc2x0 C. Lubrajel CG is a clathrate formed by the reaction of glycerin and methylmethacrylate.
The polyglyceryl methacrylate is combined with the silicone in an amount of 1-10% and preferably 1-5%.
The silicone employed for combination with the polyglyceryl methacrylate may be cyclomethicone and/or dimethiconol and/or dimethicone copolyols of varying molecular weight. Dimethicone copolyol is a copolymer of dimethlsiloxane and polyethylene oxide or propylene oxide.
Suitable emulsifiers include polyethylene glycol 20 sorbitan monolaurate (Polysorbate 20), polyethylene glycol 5 soya sterol, sorbitan tristearate, sorbitan trioleate, glyceryl, monopalmitate, diethanolamine cetyl phosphate, glyceryl monopalmitate, glyceryl monostearate, polyethylene glycol 100 stearate, polyethylene glycol 20 stearyl ether (Brij 78, Steareth 20), polyethylene glycol ether of lauryl alcohol (Laureth 23), polysorbate 80 (Tween 80), lecithin, etc. The emulsifier may constitute a single emulsifier or a mixture of two or more of these emulsifiers or others which are approved for cosmetic use.
The emulsifier is employed in approximately the same amount as the silicone i.e., 1-10% and preferably 1-5%.
The composition of the invention is recovered as a clear, transparent, hydrophilic gel. No separate gelling agents are required for its formation.
The polyglyceryl methacrylate containing about 50% water will be present in the composition of the invention in an amount of 80-98% preferably 90-98%.
The skin treatment compositions of the invention are prepared by the steps of mixing the polyglyceryl methacrylate, silicone and emulsifiers to form, a uniform, homogeneous mixture and then applying pressure in the range of about 13,000 to 50,000 psi forming a stable microemulsion.
The microemulsion produced following such compression when subjected to high speed centrifuging for two or more hours does not show any evidence of separation.
The invention additionally provides a method for treating skin for replenishing moisture in the skin which includes the step of applying to the skin a composition in accordance with the invention one or more times a day.
If the composition is intended for use to promote the healing of burned skin or to treat irritated or infected skin, the composition will have had incorporated therein an effective amount of panthenol (d- or dl-), fibronectin, allantoin, amino acid complex, etc.
The composition of the invention i.e., polyglyceryl methacrylate:silicone has been found to possess layering properties lending itself to formulation as a medical device particularly adapted for use as a carrier for various treatment agents such as: phenols, urea, aloe vera, etc.